11.2.2 tick-n Probes

The tick-n probes
fire at fixed intervals, at a high interrupt level on only one
CPU per interval. Unlike
profile-n probes,
which fire on every CPU,
tick-n probes fire
on only one CPU per interval and the CPU on which they fire can
change over time. The units of n
default to a frequency expressed as a rate of firing per second,
but the value can also have an optional time suffix as shown in
Table 11.1, “Valid Time Suffixes”, which specifies either a
time interval or a frequency.

The tick-n probes
have several uses, such as providing some periodic output or
taking a periodic action.